Selector switch



Jan. 24, 1928. 7

SELECTOR SWITCH Filed June 26, 1923 ma /7mm.- flay/ad if my fra/M/J 001m OMr/w I! cffel e/ra Falcnted Jan. 24, 1928.

UNITED STATES DOUGLAS H. KING, OF IRVINGTON, NEYV JERSEY; FRANCIS J. IDOXVD, OF BROOKLYN, NEW YORK, AND CHARLES "W. STEVENS, OF ARLINGTON, NEW JERSEY, AESIGNORS T WESTERN ELECTRIC COMPANY. INCORPORATED, OF NEW YORK, N. Y., A GOR- PORATION OF NEW YORK.

SELECTOR SWITCH.

Application filed June 26, 1923. Serial No. 647,827.

The object of this invention is to provide an improved switch of simple and inexpensive construction for use in automatic telephone systems in various capacities, such as a line finder, line switch or register.

A feature of this invention is an arrangement whereby the energy transmitted to the moving member of the switch is distributed more evenly by applying the motive power to the shaft at a point midway between its supports.

Another feature is the provision of a bank of terminals with the contact segments placed upon the plane surfaces of the switch bank whereby they are rendered readily acccssible.

Other features will appear from the detailed description.

In the drawing:

Fig. 1 is a side view, and Fig. 2 a front *iew of a switch constructed in accordance with the invention. Fig. 3 is a view of the back stop, the stepping pawl, and the ratchet wheel. Fig. 4 is a sectional view of the moulded bank showing the shape of the terminal punchings and the form in which they are assembled and Fig. 5 is a view of a section of the brush arm as shown at 55, Fig. 1.

Referring to the drawing 1 indicates the main frame to which is secured by bolts 10, amouldcd bank of terminals 3, at), semi-circular in formation. The opposite end of the bank 8 is secured by bolts 11 to an angular piece of metal 2 of the frame. The moulded bank 3 consists of a plurality of terminals arranged in rows in the form of the arc of a circle, as shown in Fig. 1, there being preferably three rows of terminals on each plane surface of the bank with the corresponding terminals of each row arranged in radial alignment. Each arcuatc row contains as many terminals as are required. In the drawing twenty sets of terminals are shown, and. assuming that six terminals are required for each trunk, such a switch would have an ultimate capacity of twenty trunks. Mounted on the free end 12 of the frame 1, is a shaft 13 which carries at each side of the bank, a brush carrier 5. The carrier 5 has two sets of brushes 14. These sets of which one only is shown, are diametrically disposed for sweeping over the terminals on the righthand face (Fig- 1) of the bank 3, and two sets of brushes 15 (of which only one set is shown) similarly disposed for sweeping over the terminals on the left-hand plane surface (not shown) of the bank 8. lVith this arrangement, it is apparent that during one complete revolution of the element 5, the twin brush sets on each side will pass over the terminals of all the trunks in the bank. The twin brush sets 14 are electrically connected together, but are insulated from the twin brush sets 15, which are also electrically connected together. The brushes 14; are connected to the collector rings 16 by a plurality of leads 17 (Fig. 5), which are electrically connected to the brushes 18 to which, at their terminals 19, the brush leads (not shown) may be attached.

The stepping magnet 4: is secured to frame 1 by a screw 20, and the armature of the magnet pivoted at 7 is extended by means of the arm 21 to the stepping pawl 22, held in engagement with the teeth of the ratchet 23 by the tension of the spring 24, whose tension is regulated by the threaded pin 25 which is fitted 'ith a lock nut 26. The end of the pawl 22 engages a stop 33 (Fig. to prevent the ratchet 23 and consequently the rotatable element 5, from stepping more than one contact at a time. The holding pawl 27 also secured to the frame 2, has one end in engagement with one of the teeth of the ratchet 23, thus preventing the element 5 from rotating in a clockwise direction.

To make the stepping magnet t self-interrupting, the arm 21 in operating causes the insulating cap 31 to force the contact spring 29 away from the contact member 30, thus opening the circuit of said magnet.

Assuming that a brush set on each plane surface of the bank is in engagement with the terminals of any trunk except the first or last, the other two brush sets will. then be disengaged from the terminals in the bank. When the stepping magnet t is operator-l, the brush sets will be rotated in a counter clockwise direction by the operation of. the stepping pawl 22 causing the brush sets to pass over the terminals of the bank in hunting for an idle trunk. If an idle trunk is not found before brush 14 breaks contact with terminal 32, the brush arms will again he stepped and the diametrically disposed brush 14: (not shown) will engage with the terminal 6 of the first line in the group and the magnet 4 will continue to operate and rotate the brush arms step-by-step to hunt foran idle trunk in the bank. This cycle of operation continues until an idle trunk is found. It will thus be seen that during one half revolution of the brush carrying element 5, the brush sets 14: and 15 will pass over the terminals of every trunk in the bank.

It is evident that because the ratchet is mounted on the shaft midway between the brush carrying arms there is no lateral thrust when the magnet is energized and consequently more certain step-hy-step movement of the brushes over the trunk terminals.

\Vhat is claimed is:

1.111 a rotary switch, a semi-circular terminal bank having two parallel plane surfaces with terminals pro ect1ng from both of said surfaces, a brush shaft, two,

engaging the terminals on one surface and 1 the other set engaging the terminals on the minal bank having two parallel plane sur faces with terminals projecting from both of said surfaces, abrush shaft, two setsof rotatable brushes attached to said shaft for engaging said terminals, one set engaging the terminals on one surface and the other set engaging the terminals on the other surface of the bank, a ratchet wheel located on said shaft between said brush sets, and driving means cooperating with said ratchet and so located between said brush sets that it is passed over by said sets in their rotation.

In Witness whereof, we hereunto subscribe our names this 13th day of June, A.

DOUGLAS H. KING. FRANCIS J. Down. CHARLES W. STEVENS. 

